Chapter 2 From Coding Form to Computer

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Chapter 2 From Coding Form to Computer
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Program Development Process

• Determine Specifications
• I/O Layout
• Processing rules
• Special Formulas
• Design the Program
• System Flow Chart
• Hierarchy / Structure Chart
• Pseudo Code / Logic Flow Chart

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Program Development Process

• Code and Enter the Program
• IDE - Integrated Development Environment
• Stand alone environment
• Compile
• Changes Source Code to Object Code
• Catches Syntax errors
• Link / Link Edit
• Combines your Object Code with other Object Code

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Program Development Process

• Test
• Adequate test data
• Finalize Documentation

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FIGURE 2.1 The Programming Process
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COBOL Coding Form

• 1 - 6 Line Numbers
• 7 Comment or Line Continuation -
• 8 - 12 Division Names Section Names Paragraph
  Names FD and 01
• 13 - 72 Everything else
• 73 - 80 Program Name

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Preparing Your Program for Execution

• Create Source Code
• Compile - converts Source code to Object or
  Machine Language
• Link / Link Edit - combines your object code with
  other needed object code to make an executable
  load module
• Execute - your load module

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FIGURE 2.3 Compile, Link, and Execute Sequence
COBOLSTATEMENTS
PROGRAM LISTING
COMPILER
OBJECTM0DULE
SUBROUTINELIBRARIES
LINKER
LOADMODULE
OTHER OBJECT MODULES
EXECUTION
OUTPUTREPORTS
INPUT DATA
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Testing and Debugging

• Errors
• Compile Time
• Syntax Errors
• Execution Time
• Logic errors
• Divide by Zero
• File Read
• Data Errors

• Debugging
• Desk Checking
• Correct Syntax
• Walk Through
• Good Test data

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Figure 2.4b COBOL Diagnostics
LINE ERR LVL ERROR TEXT 60 0138 W Period
assumed before IF 63 0787 E Undefined
symbol WRTE 64 0593 E No corresponding
active scope For END-IF seniorce has 1
Warning 2 E Level messages
COBOL statement number where error occurred
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FIGURE 2.6 Erroneous Input Data
JOHN ADAMS 090POLITICAL SCI AMELIA
EARHART 120AVIATION ORVILLE WRIGHT 115ENGINEER G
EORGIA OKEEFE 125ART MERIWETHER
LEWIS 115TRAVEL JOHN KENNEDY 115POLITICAL
SCI ALEX BELL 090ENGINEERING EMILY
DICKINSON 085LITERATRUE JOHN ROEBLING
115ENGINEERING
Engineering is spelled incorrectly
Data entered in wrong columns
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COMMON BUSINESS ORIENTED LANGUAGECOBOL

• Structured
• Standard
• English Like

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Historical Facts

• Development began 1959 with Grace Hopper
• ANSI -- CODASYL Committee
• COBOL 68 first approved standard version
• COBOL 74
• COBOL 85
• COBOL 9x

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More Facts

• WWW.ANSI.ORG
• 150 - 20Obillion lines of source code
• 40 - 50 of applications
• GUI
• Object-Oriented

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End of Chapter 2